Studies on the synthesis and antibacterial activity of new zwitterionic carbapenems

Novel lbeta-methylcarbapenems having cyclic sulfonamide moieties: synthesis and evaluation of in-vitro biological activity - part II

The synthesis of a new series of 1beta-methylcarbapenems having cyclic sulfonamide moieties is described. Their in-vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of a substituent on the pyrrolidine ring was investigated. One particular compound IIIe having a [1,2,5]thiadiazolidin 1,1-dioxide moiety showed the most potent antibacterial activity.

Synthesis and in-vitro activity of new 1beta-methylcarbapenem derivatives as antibacterial agents

The synthesis of a new series of 1beta-methylcarbapenems having pyrrolidine and piperidine moieties is described. Their in-vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of substituents on the pyrrolidine ring was investigated. A particular compound III b having an oxime-pyrrolidine moiety showed the most potent antibacterial activity.

Synthesis andIn-Vitro Activity of Novel 1β-Methylcarbapenems Having Spiro[2,4]heptane Moieties

The synthesis of a new series of 1beta-methylcarbapenems having spiro[2,4]heptane moieties is described. Their in-vitro antibacterial activities against both gram-positive and gram-negative bacteria were tested and the effect of substituents on the pyrrolidine ring was investigated. Most compounds were shown to be more active than the compared meropenem and imipenem against Escherichia coli. One particular compound, IIIb, having hydroxy a moiety showed the most potent antibacterial activity.

Novel lbeta-methylcarbapenems having cyclic sulfonamide moieties: synthesis and evaluation of in vitro antibacterial activity

The synthesis of a new series of 1beta-methylcarbapenems having cyclic sulfonamide moieties is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of substituent on the pyrrolidine ring was investigated. A particular compound (IIIi) having 2-methyl-[1,2,6]thiadiazinan-1,1-dioxide moiety showed the most potent antibacterial activity.

Synthesis and antibacterial evaluation of 1β-methyl-2-[5-(1-methoxyimino-2-substituted sulfonamide ethyl)pyrrolidin-3-ylthio]carbapenems and their related compounds

The synthesis of a new series of 1beta-methylcarbapenems having methoxyimine and substituted sulfonamide moieties is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of substituents on the pyrrolidine ring was investigated. A particular compound (IIIc) having methylaminosulfonamide moiety showed the most potent antibacterial activity.

Synthesis and in vitro activity of a series 1β-methylcarbapenem derivatives

The synthesis of a new series of 1beta-methylcarbapenems having pyrrolidine and piperidine moieties is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of substituent on the pyrrolidine ring was investigated. A particular compound (IIIb) having hydroxypyrrolidine moiety showed the most potent antibacterial activity.

Synthesis and biological evaluation of 1β-methylcarbapenems having cyclic thiourea moieties and their related compounds

The synthesis of a new series of 1beta-methylcarbapenems having cyclic thiourea moieties is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of substituent on the pyrrolidine ring was investigated. A particular compound (IIId) having piperazine thiourea moiety showed the most potent antibacterial activity.

Synthesis and Antibacterial Activity of 1β-Methyl-2-[5-(1,2-Disubstituted Ethyl)Pyrrolidin-3-ylthio]Carbapenem Derivatives

The synthesis of a new series of 1beta-methylcarbapenems having a 5-(1,2-disubstituted ethyl) pyrrolidine moiety is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of the substituent on the pyrrolidine ring was investigated. A particular compound IIIf having a 1-methoxyimino-2-carbamoylethyl substituted moiety showed the most potent antibacterial activity.

Synthesis and biological activity of 1β-methyl-2-[5-(2-N-substituted aminoethylcarbamoyl)pyrrolidin-3-ylthio]carbapenem derivatives

The synthesis of a new series of 1beta-methylcarbapenems having the substituted aminoethylcarbamoylpyrrolidine moiety is described. Their in vitro antibacterial activities against both Gram-positive including MRSA and Gram-negative bacteria were tested and the effect of substituent on the pyrrolidine ring was investigated. In particular, the compound 11g having piperazinyl urea moiety showed the most potent antibacterial activity and 11k exhibited excellent anti-MRSA.

Synthesis and antibacterial activity of 1beta-methyl-2-[5-(N-substituted-2-hydroxy iminoethyl)pyrrolidin-3-ylthio]carbapenem derivatives

The synthesis of a new series of 1-methylcarbapenems having the substituted thiazolopyrrolidine moiety is described. Their in vitro antibacterial activities against both gram-positive and gram-negative bacteria were tested and the effect of substituent on the pyrrolidine ring was investigated. In particular, compounds 12b and 12k showed the most potent antibacterial activity.

Synthesis and antibacterial activity of 1beta-methyl-2-(5-substituted thiazolo pyrrolidin-3-ylthio)carbapenem derivatives

The synthesis of a new series of 1beta-methylcarbapenems having the substituted thiazolopyrrolidine moiety is described. Their in vitro antibacterial activities against both Gram-positive including MRSA and Gram-negative bacteria were tested and the effect of substituent on the thiazole ring was investigated. A particular compound (28c) having 4'-amide substituted thiazole moiety showed the most potent antibacterial activity.

Novelties in the field of anti-infective compounds in 1999

In 1999 the number of new compounds reported in the anti-infective field decreased significantly in comparison with previous years, especially for antifungals. The reported new compounds are mainly directed against Staphylococcus aureus isolates resistant to methicillin. Few derivatives were reported in the field of anti-infectives for gram-negative bacteria. At the moment, we are in a period of discovery as we await novel compounds that could issue from new engineering.

Low convulsive activity of a new carbapenem antibiotic, DK-35C, as compared with existing congeners

Since carbapenems and cephalosporins have been suggested to induce convulsive side effects through an inhibitory action on the central gamma-aminobutyric acid (GABA)-mediated inhibitory transmission, the present study evaluated the convulsive activity of a new carbapenem antibiotic (1R,5S,6S)-6[(R)-1-hydroxyethyl]-2-[(3S,5S)-5(S-methyl-4thiomorpholin ylcarbonyl)pyrrolidin-3-thio]-l-methylcarbapen-2-em-3- carboxylic acid (DK-35C) in in vitro and in vivo experiments, in comparison with cefazolin, imipenem and meropenem. In in vitro experiments, their abilities to inhibit [3H]muscimol (5 nM) binding to GABA(A) receptors were measured using crude synaptic membranes prepared from the rat cerebral cortex. The concentrations (mM) of the antibiotics which inhibit 50% of the specific binding, were 0.6 for imipenem, 1.8 for cefazolin, 15.4 for DK-35C and 27.6 for meropenem. In in vivo experiments, intracerebroventricular (i.c.v.) injections of cefazolin, imipenem and DK-35C induced convulsions in a dose-dependent manner in rats. The doses (nmol/rat) of the antibiotics which induce convulsions in 50% of rats, were 57 for imipenem, 96 for cefazolin, 377 for DK-35C and >3000 for meropenem. In the mouse pentylenetetrazole (PTZ) convulsive model, intravenous pretreatment with cefazolin (800 mg/kg) or imipenem (200 mg/kg) shifted the dose-response curve of PTZ (i.p.) to the left, indicating enhancement of the convulsive activity of PTZ. However, pretreatment with cefazolin, meropenem or DK-35C at a dose of 400 mg/kg did not produce any marked effects on the convulsive activity of PTZ compared with the saline vehicle-pretreated control. The results clearly demonstrate a good correlation between in vitro GABA(A) receptor binding assay and in vivo i.c.v. convulsive model using rats, and suggest that DK-35C may possess a relatively weak convulsive activity mediated through an interaction with GABA(A) receptors.

Synthesis and antibacterial activities of new 1 beta-methylcarbapenems having a 1,3-diazabicyclo[3.3.0]octan-2,4-dione moiety

The synthesis of a new series of 1 beta-methylcarbapenems having a 1,3-diazabicyclo[3.3.0]octane-2,4-dione moiety is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bateria are determined and the effect of substituent on the bicyclic ring as well as stereoisomerism was investigated.

Synthesis and antibacterial activity of 1-beta-methylcarbapenem having a 1,3-diazabicyclo[3.3.0]octan-4-one moiety

The synthesis of new series of 1-beta-methylcarbapenems having a 1,3-diazabicyclo[3,3,0]octan-4-one moiety is described. Their in vitro antibacterial activities against both Gram-positive and Gram negative bacteria are reported and the effect of the substituent on the bicyclic ring was investigated and was in agreement with findings from our previous studies.

Interactions of biapenem with active-site serine and metallo-beta-lactamases

Biapenem, formerly LJC 10,627 or L-627, a carbapenem antibiotic, was studied in its interactions with 12 beta-lactamases belonging to the four molecular classes proposed by R. P. Ambler (Philos. Trans. R. Soc. Lond. Biol. Sci. 289:321-331, 1980). Kinetic parameters were determined. Biapenem was readily inactivated by metallo-beta-lactamases but behaved as a transient inhibitor of the active-site serine enzymes tested, although with different acylation efficiency values. Class A and class D beta-lactamases were unable to confer in vitro resistance toward this carbapenem antibiotic. Surprisingly, the same situation was found in the case of class B enzymes from Aeromonas hydrophila AE036 and Bacillus cereus 5/B/6 when expressed in Escherichia coli strains.